The coding of high definition moving images, for television or film, requires in the current state of the art the use of several compression cores in parallel, these being coding circuits or processors for data compression. The image is thus chopped into several zones, for example into horizontal or vertical bands or into panels, each image zone or portion being coded by a dedicated compression core.
The output bit rate regulation utilized in MPEG type video encoders is carried out with the aid of a regulating loop acting on the DCT coefficients quantization step. An increase in the quantization step results in a reduction in the coding bits required for coding these coefficients and hence in the output bit rate and vice versa.
In the processing of the high definition image, the quantization step of each encoder is regulated as a function of the data bit rate assigned to it. Jumps in quantization step at the boundary between bands or panels may, consequently, betray the chopping of the image.
An aim of the invention is to alleviate the aforesaid drawbacks.